Is the drivers' briefing compulsory?

Yes, whenever the event's Supplementary Regulations say a briefing will be held. GCR 121 requires competitors to attend any briefing required by the regulations or the Stewards.

The 2026 MSA National ROK Sporting Regulations (5.2) add that failing to attend without properly excusing yourself may lead to a R3 000 fine or, at the Clerk of the Course's discretion, a 3-place grid penalty. Other series set their own penalty in their regulations.